In recent years, as the number of pixels in solid-state image sensors has increased, sizes of pixels of the solid-state image sensor have been decreasing. However, in a planar type solid-state image sensor that is widely used, since photoelectric conversion units are two-dimensionally arranged as pixels, when sizes of pixels are reduced, areas of photoelectric conversion units are also reduced. Therefore, in the planar type solid-state image sensor, as the number of pixels increases, an aperture ratio and light collection efficiency decrease, and sensitivity decreases.
Here, in recent years, a vertical spectral type solid-state image sensor that separates light in a light incident direction by laminating photoelectric conversion units using a photoelectric conversion film formed of an organic material has been proposed.
For example, Patent Literature 1 discloses a solid-state image sensor in which organic photoelectric conversion films for absorbing each of blue light, green light and red light are laminated. In the solid-state image sensor disclosed in Patent Literature 1, a signal of each color is extracted by performing photoelectric conversion on light corresponding to that color in each of the organic photoelectric conversion films.
In addition, in Patent Literature 2, a solid-state image sensor in which an organic photoelectric conversion film that absorbs green light and a silicon photodiode are laminated is disclosed. In the solid-state image sensor disclosed in Patent Literature 2, first, a signal of green light in the organic photoelectric conversion film is extracted, a difference of a penetration depth of light in the silicon photodiode is then used to separate colors of blue light and red light, and signals of blue light and red light are extracted.